Yeah, that's the problem I'm seeing with the Life360 integration. When I check the logs, the is an error generated (I mentioned it in another post somewhere). So Life360 has me in the right place but something breaks with the HE/Life360 connection.
Tasker has never missed a report but it is sometimes delayed in comparison to Life360. Not a big deal for departures but an irritant for arrivals.
Ya, they definitely do go to sleep intermittently. I'm not sure if a lack of cell service changes that calculus at all. You can test this for yourself at home by sniffing your network, otherwise it's pretty common knowledge.
@thomasruns If you are referencing iPhones then your statement is incorrect. The biggest issues with iPhones is that they go into deep sleep mode and turn off 99% of their listening ports to conserve battery. They wake up ~every 10 minutes for full port capabilities. Only mDNS related services can wake up the phone.
Give it a try and place a RM notification to do a TTS alert for the next 24 hours. You won't get great sleep that evening as your speakers will be going off every 10 minutes.